- Compton edge
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In spectrophotometry, the Compton edge is a feature of the spectrograph that results from the Compton scattering in the scintillator or detector. When a gamma-ray scatters off the scintillator but escapes, only a fraction of its energy is registered by the detector. This leads to a spectrum of gamma-rays in the data that is not really there. The highest energy that occurs from this process is the Compton edge.
Background
In a Compton scattering process, an incident photon collides with an electron in a material. The amount of energy exchanged varies with angle, and is given by the formula:
or
- E is the energy of the incident photon.
- E' is the energy of the outgoing photon, which escapes the material.
- me is the mass of the electron.
- c is the speed of light.
- θ is the angle of deflection for the photon.
The amount of energy transferred to the material varies with the angle of deflection. As θ approaches zero, none of the energy is transferred. The maximum amount of energy is transferred when θ approaches 180 degrees.
It is impossible for the photon to transfer any more energy via this process, hence there is a sharp cutoff at this energy giving rise to the name Compton edge.
See also
- Gamma ray spectroscopy
- Compton suppression
Categories:- Spectroscopy
- Physics stubs
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